Generally speaking, most electronic clinical thermometers have rigid plastic sheath and may thus hurt the feeble patients. In particular, it is extra dangerous to probe the anus temperate of children.
As disclosed in U.S. Pat. No. 6,379,039, a clinical thermometer is characterized in that a flexible probe stem is connected to a sensor cap. In addition, the probe stem is made of thermoplastic elastomer (TPE) to make the probe stem soft and flexible. However, the soft, flexible probe stem is unable to provide sufficient strength to connect with the sensor cap tightly due to the existence of flexion and deformation.